Gas lift valve



L- L. CUMMINGS GAS LIFT VALVE Sept. s, 1953 3 sheet's-.sheet 1 FiledJuly 18, 1949 ATTORNEY Sept. 8, 1953 Filed July 18, 19.49

L. L. CUMMINGS GAS LIFT VALVE 3 Sheets-Sheet 2 es//e @Umm/ngo INVENTOR.

A 7' TOR/VEY Sept. 8, 1953 L. L. cUMMlNGs 2,651,319

GAS LIFT VALVE Filed July 18, 1949 3 Sheets-Sheet 5 INVENTOR. Y

A-roR/vfy Patented Sept. 8, 19.5.3

of Texas Tek., ass'igltp' Tex., a corporation iiiiiti .nity is, 1949,seritti No. 105279 9 claims. (c1. iamiss) 4 i' ufr-if ganterie andmoreparticular y o a alue ansfcontrolling the admission `fgs"cirjetir presesure into a column' of fluid t" raise the fluid out ofthe well.

Air or gas lift valvfs @nimonly employed for admitting lifting gasjunger pressure into a fluid column to be raised from the well,Aconventionaiiy compriseay structurant/ ing avalvei port for controllingthe admission of the gas; The valve will normallyl be loaded toisomepedetermined pressure in asuitable manner, as by a pressure loaded Ii'iblb'llowsmtvpe dlaphragrn or compression botlhto maintain the valveinclosed o sition until the pres- Slile f the lifting gels iods' th'e p-stprs# sure of thevalve. Such Valves are Sirlj'A t toa number of variableswhich aifettl ratih, inluding the hydrostatic' netta of tnf nii c ininto be lifted,` the weight of the" lifting gf o1urnr'i, and the effect oftemperature on the v lveparts. Since gas lift valves arenoiainstalled'in a series along' a tubing string tnt which thegfliiidis tobe lifted, thse variables at ct` the lValve in such manner asta marfeitdinicuit' tddeter-g mine which valve iii" the siries ievpfratingat anyparticular tinte; inf nient instantes may cause a higher gasfiiiclrt'ith s to eiicieilil'yL lift tliefli necessary wastage of lift The valve4in accordancew vention has frfits'priipl provision of' a. novel valve'strictiirewiiicii win inviate dificulties of the type enumerated andprovide' a valve which iniiitiy' despite win 0pefateie variations oftheni'tnedi J An important objeet is tf structure einploving nipioved meansfor loading the valve to a pre sletprlessue whichw'ill not be subject toVariatlons due to in t 11`l0 Y ing pressure, teinieifaturfemn gascoluzi'in weight.

Another Objectis to` provid in extent and responsive to a a 1 "o`wNpressure' differential relative Ato the pre-set pressure of the Valvel Amore Sooo'iflo .obioot.is.,tlioolorioe of.. e valve which islOadedbyuapomination of a bellows type diaphragrn anda coil spring in tensioni i Another object is. the. Provision of'oflriohol icai gripping,moolian'sni for .rostrarinatlio opening and closing movements of thevalve fOI operation within apre-determined range of Dres# s ures aboveand below the pre-set pressure of tho valvo-` i `VAdirltional objectsand advantages will become apparent from the following detailed devconjunction with the ace companying drawings ,which illustrate severaluseful' embodiments in accordance with this invention.

Inthedrawingsz Fign l is a more or less schematic view of a Well showingthefvalve meaiisin accordanceV with this iriventioninstaue'd :mathe flowtubing; v Fig. 2 is a longitudinal sectional View of one of the valvemeans, showing the parts thereof in their respective positions when thevalve iS olosdi,

Fig. B is a somewhat enlarged View generally similar to Fig. 2 showingthe valve in the open position; t

Figs/i, 5', 6 kand 7 arel cross-sections' taken respectively'-alonglines 4-`4, 5-5, 6 6 and 1'- l ofFig.3v;

Fig. 8 is an' enlarged fragmentary view in lon'-A gitudinal sectiontaken generally lalong line 8-'8 of Fig. 4 showingthe' details of amechanical lustrated in Figs. 1 and 2 Figs. 9 and 10 illustrate twoadditional em'- bodiments of the mechanical Agrippingrv mecha-V nis 11f1;and

Fig. 11 is an enlarged fragmentary View of the valve' seat'.v

eferrng to the drawings and Fig', 1 in particu1ar"', therev iss'hownaWell Il lined With the f having an inlet'pipe la connected to` itsup'per end. A conventional string of tubing I4 extends" through the boreof casing I 2 anda conventional packer element l5 isins'tallecl'betweenthe tubing and casing above the ,lorootuoioe horizorrof theft/ell toform a fluidtight'seal `irrjthe annularspace between the tublng a ncl cas1ngtodirect'ther well fluid into the V.tubing throughoponingsltrot/idool; therein for. this, purpose ,Ther tubing.oooiontional.oasinsrioad .ll adopted. to forel a ifiluidrtiaht, Seal.bott/ oon tho tubing and casing above inlet pipe I3. The upper endofutubing ldle'ads to anv suitable tankpr other'receptacle (notlshow'n)for the fluid discharged from the tubing. Valve means, in agi'vontonr.id'iotoo .goof .l o. S'll, ,are installed alone tho exterior f the`tubing vin a more or less conventional series arrangement for admittinglifting gas to the interior of the tubing serially at spaced pointstherealong. Each of the valve means I is connected at its upper end to anozzle I9 which communicates with the interior of the tubing and lugsare positioned on the tubing to support the lower ends of the respectivevalve means.

Referring now to Figs. 2 and 3, each of the valve means I8 includes atubular casing composed of an upper section 2I and a lower section 22.Upper section 2l is provided adjacent its lower end with a plurality ofradial slots 23 through which gas or other fluid may be admitted to theinterior of the casing. Section 2I is provided with an internal shoulder24 located just above slots 23 on which is mounted a removable annularseat ring 25 (see Fig. 1l) having a central port 26, the upper edge ofwhich is upwardly and outwardly tapered to form a valve seating surface21. Seat ring 25 is held in place on shoulder 24 by means of suitableset screws 28 extending through the wall of section 2I and may beremoved to permit replacement of the seat ring in the event it becomesworn in service. A seal ring 29, such as a conventional D-ring, isinstalled in the periphery of the seat ring 25 above set screws 28 toform a fluid-tight seal between the exterior of the seat ring and thewall of section 2 I.

The upper end of upper section 2l is internally threaded at 30 and isprovided with a second internal shoulder 3l below threads 30 forsupporting a spider 32. A valve cage 33 is screwed into the upper end ofsection 2I above spider 32 and contains a generally conventional annularvalve seat 34 and a gravity operated check valve 35, provided withradial guide wings 35a, mounted above seat 34 to close the latteragainst passage of fluid downwardly therethrough. The upper end of cage33 is internally threaded at 36 for the reception of a choke bushing 31and one end of a threaded nipple 38, the opposite end of which isadapted to be screwed into the outer end of nozzle I9 to establishcommunication between the valve means and the interior of tubing I4. Aflexible tubular bellows 39 of generally conventional form, is mountedin the bore of upper section 2|, the ends of the bellows being `closedby upper and lower bellows adapters 40 and 4I, respectively, to form aclosed chamber within the bellows for conning a pressure fluid undersuitable pressure. Upper bellows adapter 49 is provided with an axialpassageway 42 through which the pressure fluid may be introduced intothe interior of the bellows and passageway 42 is closed by a threadedplug 43. The upper adapter is xedly connected to the center of spider32, leaving the lower end of the bellows free to move axially of thecasing in response to expansion and contraction of the bellows. Atubular guide 44 surrounds bellows 39 and has its upper end fastened toupper adapter 4U. Its lower end surrounds lower adapter 4I and isslidable thereover so as to permit movement of the bellows relative tothe guide. Guide 44 is provided with a plurality of openings 45 fordischarge of fluid or detritus which may be trapped between the guideand the convolutions of the bellows. Lower bellows adapter 4I carries avalve disk 46 adapted to cooperate with seat 21 for opening and closingport 26. The lower face of valve disk 46 may be faced with a sealing`disk 41 constructed of rubber or other resilient material to form ailuidtight seal with seat 21 while preventing metal-to-y metal contactbetween the valve and seat. The

4 effective cross-sectional areas of port 26 and of the bellows arepreferably made substantially equal for purposes to be describedhereinafter, although other dimensional relationships for these partsmay be employed without detracting from the other useful and importantfunctions of the valve means.

Upper section 2l of the valve casing is connected to lower section `22by means of a solid connector bushing 48 which is interposed betweenthese sections and has its opposite ends threadedly connected thereto.Bushing 48 has an axial bore 49 for slidably guiding therethrough acylindricalvalve stem 50, the upper end of which is rigidly connected tothe centers of valve disk 4B and lower bellows adapter 4I. A coil spring5I is mounted in the bore of lower section 22 and has its opposite endsconnected to upper and lower bushings 52 and 53, respectively, which areslidable in the bore of section 22. The lower end of stem 50 is rigidlyconnected to upper spring bushing 52, and lower spring bushing 53 has athreaded adjusting bolt 54 connected thereto and screwed through thecenter of a cap 55 closing the lower end of section 22. The outer end ofbolt 54 is squared at 56 for application of a wrench or other tool whichmay be employed to turn the bolt. By suitable adjustment of bolt 54,tension is applied to coil spring 5I and thence to stem 5D to therebynormally urge valve disk downwardly onto seat 21 by the tension in thecoil spring.

By means of the described connection between spring 5I and bellows 39,it will be evident that valve 46 will normally be urged to the closedposition on seat 21 by a combination of expansive pressure of thebellows and the tensional force exerted by spring 5l. Any desiredcombination of these forces may be employed to pre-set the valve to adesired anti-opening pressure. Bellows 39 may be loaded at atmosphericor superatmospheric pressure, or may even be evacuated to asub-atmospheric pressure, and the tension on spring 5I in each case maybe correspondingly adjusted to provide a total valve-closing force ofthe desired magnitude. For example, if it is desired to load the valveto maintain it closed to a pressure of, say, 500 pounds per square inch,the bellows may be loaded to 250 pounds per square inch and spring 5Iwill then be adjusted to apply a tensional force of 250 pounds persquare inch. Obviously, other combinations of the bellows and springloadings may be employed to provide the total desired loading of 500pounds per square inch.

The length of stem 50 is dimensioned so that the distance between theupper face of spring bushing 52 and the'lower face of connector bushing48 will limit the upward movement of the stem and, therefore, the lengthof travel of valve disk 46 relative to seat 21, to whatever length oftravel may be desired to obtain full opening of port 26. This limitationof the axial movement o the valve also serves to prevent unduecontraction of the bellows under the opening force of the lifting gas.

In employing gas lift valves of the type described, it is desirablejthat the valve open and close with a snap action, tthat is, whenopened, the valve should move quickly from its fully closed to itsfullyopen position, so that the lifting gas may be admitted to the fluidcolumn in the tubing in puifsor jets of substantial volume. Similarly,the valve should return from its fully open position tothe fully closedposition in a springs es and the lthereby betweenr-rba11s stand uppercani surface 'broken linesFig. 8). Vvalve to'close, a downwardlydirected foroe must anowvbans 64 to slip over the outer `earn `member tounder 'sure o'f,j say,f 1Q `pounds persquarje inch, and "Iow'errs'uriface'11""1 "may be `'taperedv at "a: relatively g mnera singiequick movement fqiiowingltne admission ofmgas and consequent rductionpressure.

or gripping elenet, 50, which is adapted thevalve against opening untilthe gas pressure applied to open lthe valve exceeds the pre-establishedsetting pr'es'sre of n the valve, as deterinined by the spring andbellows loading, by Sonie pre-determined increment ad whichthe'functions to hold the valve open until the pressure of the liftinggas has been decreased below the preestablished setting pressure of 48is provided With a cam member et, 'which away the portion of the -i-ov'eupwardly past balls 764, this` `ihoir'ement being resisted by the radial'r're'ssilireV exerted by frictin'al forces developed (Figs. 3 andv'Iliereuponin order for the the Valve by` a steeperfangl or smallerradius y'of curvature to allow balls 64 to slip over the periphery ofcam the casing has increased by an increment of pounds per square inch,attaining a pressure of be' exerted on the valve sternl suiiio-ient 5toove'rcome the "compressional and fr-iction'al forces which will now be`exertedbetween the .balls'64 kand lower earn surface 61. :taperedsomewhat more steeply than upper flange rThe llatter will .be

surface B6, or out on a'srnallervra'dius (see Figp8 particularly), solthat somewhat greater force must be exerted in closing the valve thanis necess'aryto open the Valve." A`The'slliaping of surfaces 66 and '61will be designed in relation tothe radius of ba1ls`64 and to thestrength of'springs 65 to provide a suitable pre-determined range ofpressures extending 'abo'veL"and*belowA the pre-set pressure of lthevalve.

of port 23 andv of the valve maybe in'acveu to operateofthebae'k--1;ress"ur'e effect of the column of'uid When this 10 poundincrease has been attained,

and upper surface 66 will be overcome, allowing cam member 60 to moveupwardly past balls 64 and thereby cause the valve to open with a snapto its fully open position. When the valve has thus opened, balls 64will now The above-described 'valve operates as follows: With the valvein the closed position, illustrated in Fig. 2, check valve 35 will beclosed under the head of the column of fluid inA tubing I4. The gaspressure will then be built up in-theannula'r space between casing I2and tubing I4 to a pressure iiow through slots 423 and port 25 into theinterior of section 2| surrounding the bellows and thence through port34, lifting check valve 35 and passing upwardly through choke 37 intotubing I4 through nozzle I9. The admission of 'gas into the tubingserves l the pressure in the latter has dropped sufliciently belowv thepre-set pres- By making the effectivey `cross-sectional areas bellows 39substantially equal, independently ing directions, said clutch meansbeing designed to require a lesser force for release in the valveopeningdirection than in the valve closing direction.

4. A valve according to claim 3 wherein said clutch means comprises acam element having upper and lower oppositely sloping cam surfaces, anda thrust member in resilient contact with said surfaces, said surfacesbeing relatively differently shaped to .fprovide greater resistance todownward movement of said stem than to upward movement thereof.

5. In a valve of the character described, a hollow casing havingopenings intermediate the ends thereof, an annular valve seat in saidcasing above said openings, a valve stem extending through said seat, avalve element mounted on said stem above said seat, a exible resilientbellows member connected to said stem above said seat for applyingcompressional closing force to said valve element, a coil springconnected to said stem below said seat for applying tensional closingforce to said valve element, both said forces being thereby combined toexert a pre-determined closing pressure on said valve element, andclutch means engaged with said stem and operative at pre-determinedpressures above and below said closing pressure to release said stem formovement respectively in the valve-opening and closing directions.

G. In a valve of the character described, a hollow casing havingopeningsintermediate the ends thereof, an annular valve seat in said casingabove said openings, a valve stem extending through said seat, a valveelement mounted on said stem above said seat, a flexible resilientbellows member connected to said stem above said seat for applyingcompressional closing force to said valve element, a coil springconnected to said stern below said seat for applying tensional closingfor-ce to said valve element, both said forces being thereby combined toexert a predetermined closing pressure on said valve element, and clutchmeans engaged with said stem and operative at pressures above and belowsaid closing pressure to release said stem for movement respectively inthe valve-opening and closing directions, the engaging surfaces of saidclutch means being shaped to require a lesser force for affectingrelease in the valve-opening direction than in the valve-closingdirection.

7. In a valve of the character described, a hollow casing havingopenings intermediate the ends thereof, an annular valve seat in saidcasing above said openings, a valve stem extending through said seat, avalve element mounted on said stem above said seat, a flexible resilientbellows member connected to said stem above said seat for applyingcompressional closing force to said valve element, a coil springconnected to said stem below said seat for applying tensional closingforce to said valve element, both said forces being thereby combined toexert a pre-determined closing pressure on said valve element, andclutch means engaged with said stem and operative at pressures above andbelow said closing pressure to release said stem for movementrespectively in the valve-opening and closing directions, said clutchmeans comprising a cam element having upper and lower cam surfaces, anda thrust member in resilient contact with said surfaces, said surfacesbeing relatively diierently shaped to provide greater resistance todownward movement of said stem than to upward movement thereof.

8. In a valve of the character described, a hollow casing havingopenings intermediate the ends thereof, a valve seat having an axialport therein mounted in said casing above said openings, a valve stemextending through said port, a valve element mounted on said stem abovesaid seat, a tubular flexible resilient bellows member connected to saidstem above said seat for applying compressional closing force to saidvalve element, a coil spring connected to said stem below said seat forapplying tensional closing force to said valve element, both said forcesbeing thereby combined to exert a pre-determined closing pressure onsaid valve element, the effective cross-sectional areas of said bellowsmember and said port being substantially equal, and clutch means engagedwith said stem and operative at pre-determined pressures above and belowsaid closing pressure to release said stem for movement respectively inthe valve-opening and closing directions.

9. In a valve of the character described, a hollow casing havingopenings intermediate the ends thereof, an annular valve seat in saidcasing above said openings, a valve stem extending through said seat, avalve element mounted on said stem above said seat, a flexible resilientbellows member connected to said stem above said seat for applyingcompressional closing force to said valve element, a coil springconnected to said stem below said seat for applying tensional closingforce to said valve element, both said forces being thereby combined toexert a predetermined closing pressure on said valve element, means foradjusting the tension of said coil spring, and clutch means engaged withsaid stem and operative at pre-determined pressures above and below saidclosing pressure to release said stem for movement respectively in thevalveopening and closing directions.

LESLIE L. CUMMINGS.

References Cited in the file of this patent UNITED STATES PATENTS

